ABSTRACT: Thirty-two imported Merino wethers of similar age were equally assigned to two dietary energy levels (2.32 and 2.74 Mcal of ME/kg) and subdivided into two feeding periods (25 and 45 days). All wethers were group-fed at 3% of their body weight daily and slaughtered at the end of each feeding period. The following performance measures and carcass traits were evaluated: average daily gain, feed efficiency, dressing %, kidney and pelvic fat, fat thickness, body wall thickness and longissimus dorsi area. The carcass of each wether was boned and proximate analysis was determined. Wethers fed on a high energy diet or those kept for 45 days on feed excelled (P<0.05) in the following measurements: final body weight, average daily gain, feed efficiency, dressing percentage, kidney and pelvic fat weight, body wall thickness, dissectible lean and fat weights and chemical fat weight in their carcasses. Also, the high energy fed group had significantly (P<0.05) more fat thickness and yielded more protein in their carcasses than those fed on the medium level of energy diet.